It is known to apply the treatment medium via nozzles onto the textile web, the application occurring on a straight section of the web or on a section of the web which is curved around a roller. Internation publication WO 91/04367 describes a treatment method where the textile web is guided in an extended condition through a narrow shaft, and where if necessary different treatment mediums, such as water, hot vapour or hot air are applied to the textile web under pressure. For the treatment of knitted goods, such as tricot, this method is unsuitable because of its relatively long unsupported lengths. A related and comparable device is made known in German document DE-A-25 21 407, where the treatment medium is sprayed onto the web and is then immediately removed from the same side of the web by suction. This procedure can be carried out both on straight and curved sections of the web. Extended action of the treatment medium on the textile web is here not possible, the case with vaporific treatment mediums. German document DE-A-19 17 759 describes the treatment of a tension-sensitive textile web, with the textile web being guided along a continuously constrained web path around rollers through which a treatment liquid flows. Forced penetration of the liquid through the textile web does occur, although its effect will not be as intensive as is possible when using nozzles.